Improving qubit coherence using closed-loop feedback

Abstract

Superconducting qubits are a promising platform for building a larger-scale quantum processor capable of solving otherwise intractable problems. In order for the processor to reach practical viability, the gate errors need to be further suppressed and remain stable for extended periods of time. With recent advances in qubit control, both single- and two-qubit gate fidelities are now in many cases limited by the coherence times of the qubits. Here we experimentally employ closed-loop feedback to stabilize the frequency fluctuations of a superconducting transmon qubit, thereby increasing its coherence time by 26\% and reducing the single-qubit error rate from $(8.5\pm 2.1)\times 10^{-4}$ to $(5.9\pm 0.7)\times 10^{-4}$. Importantly, the resulting high-fidelity operation remains effective even away from the qubit flux-noise insensitive point, significantly increasing the frequency bandwidth over which the qubit can be operated with high fidelity. This approach is helpful in large qubit grids, where frequency crowding and parasitic interactions between the qubits limit their performance.

arXiv comment15 pages, 7 figures

References in corpus (36)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Charge insensitive qubit design derived from the Cooper pair box
• A Quantum Engineer's Guide to Superconducting Qubits
• Logic gates at the surface code threshold: Superconducting qubits poised for fault-tolerant quantum computing
• Superconducting Qubits: Current State of Play
• Randomized Benchmarking of Quantum Gates
• Dynamical decoupling and noise spectroscopy with a superconducting flux qubit
• Decoherence in a superconducting quantum bit circuit
• 1/f noise: implications for solid-state quantum information
• The Flux Qubit Revisited to Enhance Coherence and Reproducibility
• Approaching Unit Visibility for Control of a Superconducting Qubit with Dispersive Readout
• Quantum feedback control of a superconducting qubit: Persistent Rabi oscillations
• Procedure for systematically tuning up crosstalk in the cross resonance gate
• Fluctuations of Energy-Relaxation Times in Superconducting Qubits
• Measurement and control of a mechanical oscillator at its thermal decoherence rate
• Decoherence benchmarking of superconducting qubits
• Correlated Charge Noise and Relaxation Errors in Superconducting Qubits
• Relaxation and frequency shifts induced by quasiparticles in superconducting qubits
• Impact of ionizing radiation on superconducting qubit coherence
• Correlating decoherence in transmon qubits: Low frequency noise by single fluctuators
• Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits
• Suppressing qubit dephasing using real-time Hamiltonian estimation
• Quasiparticle relaxation of superconducting qubits in the presence of flux
• Initial decoherence in solid state qubits
• Quantum Feedback Control of Atomic Motion in an Optical Cavity
• Bounding quantum gate error rate based on reported average fidelity
• Spectroscopy of low-frequency noise and its temperature dependence in a superconducting qubit
• Two-level systems in superconducting quantum devices due to trapped quasiparticles
• Characterizing and optimizing qubit coherence based on SQUID geometry
• Qubit metrology of ultralow phase noise using randomized benchmarking
• Phase-modulated entangling gates robust to static and time-varying errors
• Restless Tuneup of High-Fidelity Qubit Gates
• Quantum-enhanced magnetometry by phase estimation algorithms with a single artificial atom
• Coherence of a driven electron spin qubit actively decoupled from quasi-static noise
• Real-time calibration with spectator qubits
• High-speed calibration and characterization of superconducting quantum processors without qubit reset

Cited by in corpus (18)

• Overcoming I/O bottleneck in superconducting quantum computing: multiplexed qubit control with ultra-low-power, base-temperature cryo-CMOS multiplexer
• Systematic study of High $E_J/E_C$ transmon qudits up to $d=12$
• Robust Quantum Gates against Correlated Noise in Integrated Quantum Chips
• A superconducting qubit with noise-insensitive plasmon levels and decay-protected fluxon states
• Real-time two-axis control of a spin qubit
• Real-time feedback protocols for optimizing fault-tolerant two-qubit gate fidelities in a silicon spin system
• Physics-informed tracking of qubit fluctuations
• Passive and active suppression of transduced noise in silicon spin qubits
• Dephasing in Fluxonium Qubits from Coherent Quantum Phase Slips
• Qubit fidelity under stochastic Schrödinger equations driven by colored noise
• Prolonging a discrete time crystal by quantum-classical feedback
• Beating the Ramsey limit on sensing with deterministic qubit control
• Efficient Qubit Calibration by Binary-Search Hamiltonian Tracking
• A quantum register using collective excitations in a Bose-Einstein condensate
• Accessing the Full Capabilities of Filter Functions: A Tool for Detailed Noise and Control Susceptibility Analysis
• Noise cross-correlations from single-shot measurements
• Iterative Adaptive Spectroscopy of Short Signals
• Characterization and cancellation of power-line-induced motional-mode frequency noise in a trapped-ion system